diff --git a/src/openttd.cpp b/src/openttd.cpp
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -188,7 +188,7 @@ static void ShowHelp()
 		"  -p password         = Password to join server\n"
 		"  -P password         = Password to join company\n"
 		"  -D [ip][:port]      = Start dedicated server\n"
-		"  -l ip[:port]        = Redirect DEBUG()\n"
+		"  -l ip[:port]        = Redirect Debug()\n"
 #if !defined(_WIN32)
 		"  -f                  = Fork into the background (dedicated only)\n"
 #endif
@@ -666,7 +666,7 @@ int openttd_main(int argc, char *argv[])
 	DeterminePaths(argv[0], only_local_path);
 	TarScanner::DoScan(TarScanner::BASESET);
 
-	if (dedicated) DEBUG(net, 3, "Starting dedicated server, version %s", _openttd_revision);
+	if (dedicated) Debug(net, 3, "Starting dedicated server, version {}", _openttd_revision);
 	if (_dedicated_forks && !dedicated) _dedicated_forks = false;
 
 #if defined(UNIX)
@@ -715,7 +715,7 @@ int openttd_main(int argc, char *argv[])
 	/* Initialize game palette */
 	GfxInitPalettes();
 
-	DEBUG(misc, 1, "Loading blitter...");
+	Debug(misc, 1, "Loading blitter...");
 	if (blitter.empty() && !_ini_blitter.empty()) blitter = _ini_blitter;
 	_blitter_autodetected = blitter.empty();
 	/* Activate the initial blitter.
@@ -945,7 +945,7 @@ bool SafeLoad(const std::string &filenam
 				 * special cases which make clients desync immediately. So we fall
 				 * back to just generating a new game with the current settings.
 				 */
-				DEBUG(net, 0, "Loading game failed, so a new (random) game will be started");
+				Debug(net, 0, "Loading game failed, so a new (random) game will be started");
 				MakeNewGame(false, true);
 				return false;
 			}
@@ -1136,7 +1136,7 @@ static void CheckCaches()
 	uint i = 0;
 	for (Town *t : Town::Iterate()) {
 		if (MemCmpT(old_town_caches.data() + i, &t->cache) != 0) {
-			DEBUG(desync, 2, "town cache mismatch: town %i", (int)t->index);
+			Debug(desync, 2, "town cache mismatch: town {}", t->index);
 		}
 		i++;
 	}
@@ -1151,7 +1151,7 @@ static void CheckCaches()
 	i = 0;
 	for (const Company *c : Company::Iterate()) {
 		if (MemCmpT(old_infrastructure.data() + i, &c->infrastructure) != 0) {
-			DEBUG(desync, 2, "infrastructure cache mismatch: company %i", (int)c->index);
+			Debug(desync, 2, "infrastructure cache mismatch: company {}", c->index);
 		}
 		i++;
 	}
@@ -1208,23 +1208,23 @@ static void CheckCaches()
 		for (const Vehicle *u = v; u != nullptr; u = u->Next()) {
 			FillNewGRFVehicleCache(u);
 			if (memcmp(&grf_cache[length], &u->grf_cache, sizeof(NewGRFCache)) != 0) {
-				DEBUG(desync, 2, "newgrf cache mismatch: type %i, vehicle %i, company %i, unit number %i, wagon %i", (int)v->type, v->index, (int)v->owner, v->unitnumber, length);
+				Debug(desync, 2, "newgrf cache mismatch: type {}, vehicle {}, company {}, unit number {}, wagon {}", v->type, v->index, v->owner, v->unitnumber, length);
 			}
 			if (memcmp(&veh_cache[length], &u->vcache, sizeof(VehicleCache)) != 0) {
-				DEBUG(desync, 2, "vehicle cache mismatch: type %i, vehicle %i, company %i, unit number %i, wagon %i", (int)v->type, v->index, (int)v->owner, v->unitnumber, length);
+				Debug(desync, 2, "vehicle cache mismatch: type {}, vehicle {}, company {}, unit number {}, wagon {}", v->type, v->index, v->owner, v->unitnumber, length);
 			}
 			switch (u->type) {
 				case VEH_TRAIN:
 					if (memcmp(&gro_cache[length], &Train::From(u)->gcache, sizeof(GroundVehicleCache)) != 0) {
-						DEBUG(desync, 2, "train ground vehicle cache mismatch: vehicle %i, company %i, unit number %i, wagon %i", v->index, (int)v->owner, v->unitnumber, length);
+						Debug(desync, 2, "train ground vehicle cache mismatch: vehicle {}, company {}, unit number {}, wagon {}", v->index, v->owner, v->unitnumber, length);
 					}
 					if (memcmp(&tra_cache[length], &Train::From(u)->tcache, sizeof(TrainCache)) != 0) {
-						DEBUG(desync, 2, "train cache mismatch: vehicle %i, company %i, unit number %i, wagon %i", v->index, (int)v->owner, v->unitnumber, length);
+						Debug(desync, 2, "train cache mismatch: vehicle {}, company {}, unit number {}, wagon {}", v->index, v->owner, v->unitnumber, length);
 					}
 					break;
 				case VEH_ROAD:
 					if (memcmp(&gro_cache[length], &RoadVehicle::From(u)->gcache, sizeof(GroundVehicleCache)) != 0) {
-						DEBUG(desync, 2, "road vehicle ground vehicle cache mismatch: vehicle %i, company %i, unit number %i, wagon %i", v->index, (int)v->owner, v->unitnumber, length);
+						Debug(desync, 2, "road vehicle ground vehicle cache mismatch: vehicle {}, company {}, unit number {}, wagon {}", v->index, v->owner, v->unitnumber, length);
 					}
 					break;
 				default:
@@ -1271,11 +1271,11 @@ static void CheckCaches()
 		}
 		UpdateStationDockingTiles(st);
 		if (ta.tile != st->docking_station.tile || ta.w != st->docking_station.w || ta.h != st->docking_station.h) {
-			DEBUG(desync, 2, "station docking mismatch: station %i, company %i", st->index, (int)st->owner);
+			Debug(desync, 2, "station docking mismatch: station {}, company {}", st->index, st->owner);
 		}
 		for (TileIndex tile : ta) {
 			if (docking_tiles[tile] != IsDockingTile(tile)) {
-				DEBUG(desync, 2, "docking tile mismatch: tile %i", (int)tile);
+				Debug(desync, 2, "docking tile mismatch: tile {}", tile);
 			}
 		}
 
@@ -1283,7 +1283,7 @@ static void CheckCaches()
 		IndustryList industries_near = st->industries_near;
 		st->RecomputeCatchment();
 		if (st->industries_near != industries_near) {
-			DEBUG(desync, 2, "station industries near mismatch: station %i", st->index);
+			Debug(desync, 2, "station industries near mismatch: station {}", st->index);
 		}
 	}
 
@@ -1291,14 +1291,14 @@ static void CheckCaches()
 	i = 0;
 	for (Town *t : Town::Iterate()) {
 		if (t->stations_near != old_town_stations_near[i]) {
-			DEBUG(desync, 2, "town stations near mismatch: town %i", t->index);
+			Debug(desync, 2, "town stations near mismatch: town {}", t->index);
 		}
 		i++;
 	}
 	i = 0;
 	for (Industry *ind : Industry::Iterate()) {
 		if (ind->stations_near != old_industry_stations_near[i]) {
-			DEBUG(desync, 2, "industry stations near mismatch: industry %i", ind->index);
+			Debug(desync, 2, "industry stations near mismatch: industry {}", ind->index);
 		}
 		i++;
 	}
@@ -1406,7 +1406,7 @@ static void DoAutosave()
 		if (++_autosave_ctr >= _settings_client.gui.max_num_autosaves) _autosave_ctr = 0;
 	}
 
-	DEBUG(sl, 2, "Autosaving to '%s'", buf);
+	Debug(sl, 2, "Autosaving to '{}'", buf);
 	if (SaveOrLoad(buf, SLO_SAVE, DFT_GAME_FILE, AUTOSAVE_DIR) != SL_OK) {
 		ShowErrorMessage(STR_ERROR_AUTOSAVE_FAILED, INVALID_STRING_ID, WL_ERROR);
 	}